John Unger says Schoep's Legacy Foundation has raised more than $25,000 since Unger and his dog, Schoep, were photographed by a friend, who posted the image to Facebook.

Before the photo was taken, Unger and his veterinarian had been considering putting Schoep down.

"Without treatment, John and I were talking about euthanasia at the end of July," Erik Haukass, the vet, told the Daily Mail. But through the unsolicited donations from people who saw the photo, Unger was able to treat Schoep and extend his life.

"Schoep is doing incredible right now," Unger said. 'The therapies that the people have donated--it's like turning back the clock a year and a half."

The foundation was created, Haukass added, when the pair "realized we had received more money than we would reasonably spend on Schoep's care."

"This 19-year-old [Schoep is] being cradled in his father's arms last night in Lake Superior," Hannah Stonehouse Hudson, the photographer, wrote in the Facebook post that sparked the outpouring. "Schoep falls asleep every night when he is carried into the lake. The buoyancy of the water soothes his arthritic bones. Lake Superior is very warm right now, so the temperature of the water is perfect. I was so happy I got to capture this moment for John. By the way, John rescued Schoep as an 8-month-old puppy, and he's been by his side through many adventures."

Hudson, a professional photographer, told the Pioneer Press that business is booming since the photo of Unger and Schoep was published--so much so that she recently hired her first employee plus an intern.

"I would say a 30 percent increase in shoots," Hudson said. "Who knew a favor to a friend would turn into this? It's completely surreal."

Because of the public's generosity, Schoep has been getting expensive joint laser treatments to reduce pain and swelling related to arthritis.